As one type of semiconductor storage device, NAND flash memory is well-known. In addition, NAND flash memory including memory cells that are three-dimensionally stacked are well-known.
In NAND flash memory, during a short period after programming, a phenomenon, known as short term data retention (STDR), occurs in which a threshold voltage distribution is greatly shifts in the negative direction. With this phenomena, it is difficult to set a read voltage used for reading data from a memory cell array to follow such a change in the threshold voltage distribution. In other words, it is difficult to set an optimal read voltage. As a result, the number of retry read operations from the NAND flash memory increases, and thus, read performance of the NAND flash memory deteriorates.